X-ray protection tube



1 Nov. 12, 1957 E. ZIELER X-RAY PROTECTION TUBE Filed June 29, 1954 Fig, 2

Fig.

INVENTOR. ERlCH ZIELER AGENT United States Patent X-RAY PROTECTION TUBE Erich Zieler, Hamburg-Fuhlsbuttel, Germany, assignor,

by mesne assignments, to North American Phlhps Company, Inc., New York, N. Y., a corporation of Delaware Application June 29, 1954, Serial No. 440,211

Claims priority, application Germany June 29, 1953 2 Claims. (Cl. 250-108) For limiting the efficacious beam of rays in medical X-ray technique, use is made of tubes of various kinds according to the purpose they have to serve. For irradiating cavities of a body, use is commonly made of cylindrical tubes, known as protection tubes, comprising an elongated part which is at an angle therewith and which determines the distance between the focal spot of the X-ray tube and the surface of the tissue to be irradiated.

Such protection tubes usually comprise a drawn metallic tube which is coated with lead to intercept unwanted X-rays. It is difiicult to manufacture such tubes due to their shape requiring the coating of lead to consist of two pieces. Practice has shown that the manufacture has to be effected with care to prevent flaws in the coating or surfaces on which corrosion is liable to occur (in sterilizing).

The invention which permits to avoid the said difliculty is based on recognition of the fact that the wavelength of the X-rays used in treating tissues located in cavities of a body is such that the lead used hitherto for limiting the radiation may advantageously be substituted by another material which also constitutes the wall of the protection tube.

The X-ray protection tube, according to the invention, which is suited more particularly for irradiating cavities of a body, consists of silver at least so far as that part is concerned which serves to limit the beam of rays and to provide protection against unwanted rays. The silver part may be constituted by a single casting.

The invention will now be described in greater detail with reference to the accompanying drawing, in which:

Fig. 1 is a cross-sectional view of a protection tube according to the invention;

Fig. 2 is a plan view, partly in cross-section, of an Patented Nov. 12, 1957 i C-ray device including the protection tube illustrated in Referring now to the drawing, Fig. 1 shows a protection tube for an X-ray device in accordance with the invention. It comprises a single casting of silver forming a first, elongated, tubular portion 1 and a slightly-tapered, tubular portion 2 at an angle with the first portion 1.

Fig. 2 shows the protection tube of Fig. I mounted in position in an X-ray device. As shown, the protection tube 1 and 2, provided with a flanged portion 3 at the bottom, is mounted by means of a surrounding member 4 on an outer, insulating envelope 5 enclosing an X-ray tube 6 or like X-ray producing device. Suitable potentials for the X-ray tube 6 are provided by a conductor 7 surrounded by a shielded, flexible cable 8. As is well known in the art, excitation of the X-ray tube 6 produces X-rays which emanate from the upper portion thereof in an axial direction through the protection tube 1 and 2.

The X-ray protection tube according to the invention, which may have the shape, for example, as shown in the drawing, no longer suffers from the disadvantage that difiiculties are encountered in joining the parts 1 and 2, more particularly since coating with a substance intercepting unwanted rays is not required due to the silver of the wall of the tubefulfilling itself the task of this coating.

It has been found that the absorbing power of silver substantially corresponds to that of lead at a voltage up to kilovolts, as used, for example, in the therapy of the cavities of a body, since the K-absorption limit of lead is located at a wavelength of 0.14 A and that of silver only at about 0.49 A.

What is claimed is:

1. An X-ray device including a protection member for entering and irradiating body cavities in X-ray therapy, said device comprising X-ray producing means, said protection member comprising a thin, elongated, metal tube serving to limit the efiicacious radiation and to intercept unwanted X-rays, said metal tube consisting entirely of silver.

2. An X-ray device as set forth in claim 1 wherein the metal tube is constituted of a single silver casting.

References Cited in the file of this patent UNITED STATES PATENTS McCartney et al. Dec. 18, 1951 

